Cathy Young is a regular contributor to Reason magazine and Real Clear Politics.

Wendy Davis, the Texas state senator and Democratic candidate for governor, catapulted to national fame last year after she held an 11-hour filibuster trying to block a bill restricting late-term abortions. Feminists and liberals hailed her as a heroine for our time: a single mom who worked her way up from trailer-park poverty to a Harvard law degree and a career in politics.

But now, this female version of the American success story seems compromised by revelations that her rise was helped by her second husband, whom she later divorced -- voluntarily giving him custody of her two daughters, including the one from her first marriage. Republicans are slamming Davis as an opportunist; Democrats defend her as a victim of sexist attacks. In fact, the complexities of her story have unsettling lessons for conservatives and feminists.

Questioning the veracity of Davis' official life story is not sexist. The bio on her campaign site says she earned her law degree "with the help of academic scholarships, student loans, and state and federal grants." It omits second husband Jeffry Davis, a lawyer who cashed out his 401(k) and took out a loan to help pay her tuition and housing in Massachusetts -- while he stayed in their Fort Worth home with the two kids.

Davis did not (as some critics are implying) lie about this part of her past. She mentioned Jeffry Davis' role in putting her through law school in interviews to two small Texas newspapers in September, months before the Dallas Morning News treated this as explosive new information. Still, she has publicly emphasized her struggle as a young divorced mother and her success as a self-made woman.

Would a male politician have gotten better treatment? If he had promoted himself as a single dad who made it on his own, and it then turned out a wife had financed his education and cared for his kids -- only to get ditched just as his career took off -- it's doubtful that the media would have been very kind. Men in politics aren't exactly spared controversy over past marital troubles. (Newt Gingrich, anyone?)

However, the criticism of Davis as a bad parent has sexist elements. In the New York Post, columnist Naomi Schaefer Riley argues that Davis has no political future because "a woman who leaves her kids is just beyond the pale," in the eyes of men and women alike. "Call it sexism if you want," writes Riley, noting that mothers who don't have custody are automatically suspect and making it clear that she's fine with the double standard.

We should call it sexism, and we should not be fine with it. Davis is by all accounts close to her daughters. Some good mothers don't fit the traditional mold.

But this issue also illustrates how sexism hurts both women and men.

A female attorney active on behalf of fathers' rights once told me that the stigma against non-custodial mothers often pushes women to fight tooth and nail for primary custody even in cases where everyone would be better off if the children lived with their dad.

If women get more flak for "leaving their children," men can get savaged for wanting to "take the children from their mother." And, with a few exceptions, feminists have supported this double standard when it favors women. They have portrayed career women who lose custody as victims of misogyny, opposed joint custody legislation, and even compared fathers' rights activists to abusers.